A visual search tab allows the user to search efficiently across broad subjects, and then returns a visual map of results, organized by topic.

iPhone and Android applications.

Dates covered

19th century-current and earlier

Updating frequency

Quarterly.

Sources

Books, journals, current research, popular magazines, reviews, radio and television broadcasts, newspapers, pamphlets, government publications, grey literature, maps, reports, theses and dissertations, and music recordings.